www.LancasterLabsEnv.com
Analysis of Alkyl PAHs And Geochemical Biomarkers
Providing comprehensive scientific resources to environmental clients worldwide.
Chuck Neslund, Manager Specialty Services
NEMC Environmental Measurement Symposium, August 5-9, 2013,
San Antonio, TX
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• Most important target analytes in damage assessment from petroleum products
• Known to originate from 2 sources
- Petrogenic
- Pyrogenic
PAHs and Alkyl PAHs
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PAHs and Alkyl PAHs
• Can be used in forensic analysis to qualitatively fingerprint petroleum sample
• Crude oils contain primarily alkyl PAHs and relatively smaller concentrations of unsubstituted PAHs
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What are Alkyl PAHs?
• Parent PAHs are 2 or more fused conjugated rings
naphthalene benz(a)anthracene
• Alkylated PAHs are the parent PAH with various alkyl groups attached
2,3,5-trimethylnaphthalene
7,12-dimethylbenz(a)anthracene
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What are Alkyl PAHs?
• Categorized by the total number of alkyl carbon atoms present
• A homolog group includes all of the isomers with the same number of carbon atoms
• C3 includes propyl, isopropyl, trimethyl and ethylmethyl
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What are Alkyl PAHs?
• Parent PAHs that are isomers of other parent PAHs are combined for reporting purposes
- phenanthrene/anthracene
- fluoranthene/pyrene
- benz(a)anthracene/chrysene
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Why do we care?
• Traditional methods focused on the 16 Priority Pollutant PAHs identified by EPA
• There are hundreds if not thousands of alkylated forms that are unaccounted for in traditional methods
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Why do we care?
• Less toxicity data available for alkyl PAHs than their parent compounds
• Alkyl PAHs are more abundant and persist longer than their parent compounds
• Analysis of alkyl PAHs in combination with the parent compounds is a better estimation of total exposure to toxic effects of PAHs
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Method Summary
• Extraction methods are relatively standard for those used for soil and water
- SW-846 3510 for waters
- SW-846 3546 for soils
• Alumina column clean-up used as needed
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Method Summary
• Tuning and calibration similar to 8270 SIM
• Alkyl PAHs calculated from a multipoint calibration
• A representative target compound is used to represent a homolog series for quantification
• Results generated for alkyl PAHs should be treated as semiquantitative
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PAHS Reported
1-Methylnaphthalene
2-Methylnaphthalene
2,6-Dimethylnaphthalene
2,3,5-Trimethylnaphthalene
Naphthobenzothiophene
Perylene
Phenanthrene
1-Methylphenanthrene
Pyrene
Retene
Total Aromatics (includes alkylated)
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(e)pyrene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Benzothiophene
Biphenyl
Chrysene
cis/trans-Decalin
Dibenz(a,h)anthracene
Dibenzofuran
Dibenzothiophene
Fluoranthene
Fluorene
Indeno(1,2,3-cd)pyrene
Naphthalene
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Alkyl PAHS Reported
C1-Dibenzothiophenes
C2-Dibenzothiophenes
C3-Dibenzothiophenes
C4-Dibenzothiophenes
C1-Fluoranthenes/pyrenes
C2-Fluoranthenes/pyrenes
C3-Fluoranthenes/pyrenes
C4-Fluoranthenes/pyrenes
C1-Benzanthrene/chrysenes
C2-Benzanthrene/chrysenes
C3-Benzanthrene/chrysenes
C4-Benzanthrene/chrysenes
C1-Naphthalenes
C2-Naphthalenes
C3-Naphthalenes
C4-Naphthalenes
C1-Fluorenes
C2-Fluorenes
C3-Fluorenes
C1-Phenanthrenes/Anthracenes
C2-Phenanthrenes/Anthracenes
C3-Phenanthrenes/Anthracenes
C4-Phenanthrenes/Anthracenes
C1-Benzo(b)thiophene
C2-Benzo(b)thiophene
C3-Benzo(b)thiophene
C4-Benzo(b)thiophene
C1-Naphthobenzothiophenes
C2-Naphthobenzothiophenes
C3-Naphthobenzothiophenes
C1-Decalin
C2-Decalin
C3-Decalin
C4-Decalin
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Method Summary
• To create SIM method large investment in establishing correct windows
• Analysis of reference oils to determine alkyl PAH windows
• Requires analysis of windowing standard at start of each tune
• Alkanes added to the calibration and analysis mix
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C2-Naphthalenes
Mass 156, 141 amu; 10.2 to 12.8 min
10.20 10.40 10.60 10.80 11.00 11.20 11.40 11.60 11.80 12.00 12.20 12.40 12.60 12.80 0
50000
100000
150000
200000
Time-->
Abundance
Ion 156.00 (155.70 to 156.70): cg1042.D\data.ms
10.20 10.40 10.60 10.80 11.00 11.20 11.40 11.60 11.80 12.00 12.20 12.40 12.60 12.80 0
50000
100000
150000
200000
Time-->
Abundance
Ion 141.00 (140.70 to 141.70): cg1042.D\data.ms
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Alkanes Reported
n-Nonacosane
n-Triacontane
n-Hentriacontane
n-Dotriacontane
n-Tritriacontane
n-Tetratriacontane
n-Pentatriacontane
Pristane
Phytane
Total Alkanes
n-Decane
n-Undecane
n-Dodecane
n-Tridecane
n-Tetradecane
n-Pentadecane
n-Hexadecane
n-Heptadecane
n-Octadecane
n-Nonadecane
n-Eicosane
n-Heneicosane
n-Docosane
n-Tricosane
n-Tetracosane
n-Pentacosane
n-Hexacosane
n-Heptacosane
n-Octacosane
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• Complex organic compounds that are
found in petroleum and show little to no
change in structure from their parent
molecules found in living organisms.
• Categorized into different classes,
terpanes, steranes and triaromatic
steroids
What are Geochemical Biomarkers?
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•Several reference biomarker compounds
are in calibration mixes
•Biomarkers grouped according to
reference used for quantification
•Analysis of reference oils key to
biomarker identification
What are Geochemical Biomarkers?
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Biomarkers reported
A1-C20-TAS
A2-C21-TAS
A3-C26 TAS(20S)
A4-C26/C27-TAS
A5-C27-TAS(20R)
A6-TAS(20S)
A7-TAS(20R)
T1-C20Diterpane
T2-C21Diterpane
T3-C22Diterpane
T4-C23Diterpane
T5-C24Diterpane
T6-C25Diterpane
T6a-C24TetracyclicTerpane
T6b-C26Tricyclic[S]
T6c-C26Tricyclic[R]
T7-C28Tricyclictriterpane[S]
T8-C28Tricyclictriterpane[R]
T9-C29Tricyclictriterpane(S)
T10-C29Tricyclictriterpane(R)
T11-Trisnorhopane(TS)
T12-Trisnorhopane(TM)
T13-Trisnorhopane
T13a-29,30-Bisnorhopane
T14-Bisnorhopane
T14a-C28,C30Bisnorhopane
T14b-C29,C25Norhopane
T15-C29-Norhopane
T16-Norneohopane
17a(H)-diahopane
T17-C30-Normoretane
T18-C30-Oleanane
T19-C30-Hopane
T20-Moretane
T21-C31-Homohopane(S)
17b(H),21b(H)-Hopane
T22-C31-Homohopane(R)
T22a-Gammacerane
T23-Homohopane
T24-Homomoretane
T25-Diploptene
T26-C32-Bishomohopane(S)
T27-C32-Bishomohopane(R)
T28-Bishomomoretane
T29-Homohopane
T30-C33-Trishomohopane(S)
T31-C33-Trishomohopane(R)
T32-Tetrakishomohopane(S)
T33-Tetrakishomohopane(R)
T34-Pentakishomohopane(S)
T35-Pentakishomohopane(R)
S4-Diacholestane
S5-Diacholestane
5a-cholestane
S6-Diacholestane
S7-Diacholestane
S8-Methyldiacholestane
S10-Methyldiacholestane
S11-Methyldiacholestane
S12-Cholestane
S14-Cholestane(20R)
S15-Cholestane(20S)
S18-Ethyldiacholestane
S19-Ethyldiacholestane
S20-Methyldiacholestane
S22-Methylcholestane(20R)
S23-Methylcholestane(20S)
S24-MethylCholestane
S25-EthylCholestane
S26-Ethylcholestane(20R)
S27-Ethylcholestane(20S)
S28-Ethylcholestane
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Why do we care?
•Very useful in forensic petroleum analysis
when alkane pattern is weathered
•Complements and enhances conventional
GC/FID fingerprinting capabilities
•Can be analyzed simultaneously with the
Alkyl PAHs.
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Results
• Specialized report format and electronic
spreadsheet
• Histograms for qualitative analysis of
PAHs/Alkyl PAHs
• Extracted ion current profiles provided for
biomarkers
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Acknowledgement
Richard Karam, Manager, Semivolatiles, Eurofins Lancaster
Laboratories Environmental
Tim Trees, Principal Chemist, Eurofins Lancaster Laboratories
Environmental
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